Assessments of security trends in Iraq vary wildly depending on who you speak to, how you count the statistics, and which period of time you study. But one thing is clear: bomb blasts, targeted killings or improvised explosive devices are still a daily occurrence in Iraq.

Last week’s coordinated attacks - leaving more than 100 people dead - set a record for the highest number of deaths in a single day in more than two years, displaying the continued ability of insurgent groups to strike. A double bombing in the capital yesterday brought July’s death toll to 245, according to a count by Associated Press.

While the US and the Iraqi government insist that security gains have been made in recent years, UN and independent analysts characterize the situation as having stabilized at an unacceptably high level of violence, albeit now concentrated in more specific areas.

Since 2009, the average number of incidents per month has gradually decreased, but the number of casualties per incident has increased, leaving - overall - a slight decrease in the level of violence, according to UN statistics. (These statistics are based on open sources and cannot always be independently verified). Others, however, say attacks are becoming less lethal and more easily foiled as weakened insurgents shift their goal from mass casualties to simply marking their presence.

Iraq Body Count, an independent tracking database, reports no drop in civilian casualties, with an average of about 4,000 killed per year since 2009.

The US troop pullout six months ago has taken the wind out of the sails of many armed groups, especially Shia groups, whose raison d’etre was opposing the occupation. But it has also led to a rebalancing of power in which politicians, militias, “terrorists” and countries in the region are vying for influence.

“The main event in Iraq, which was postponed for many years due to the US presence, is the struggle among Iraqis to control the country,” argues Michael Knights, a fellow at the Washington Institute for Near East Policy, and author of several books on Iraq. Analysts expect the struggle to continue bubbling along for some time to come.

Here are a few of the drivers of conflict in Iraq:

Dysfunctional parliament: Iraqi politics are young - only truly born after the US withdrawal - and its players are still learning how to make democracy work. “The main driver of violence in Iraq is the dysfunctionality of the political process and the polarization between [Prime Minister Nouri] al-Maliki and his opponents,” says Joost Hiltermann, Iraq analyst with the International Crisis Group. The Shiite rulers do not know how to absorb minorities into the fold, and many questions around the constitution, federalism and power/resource-sharing remain unanswered. The inability to reach agreement has left the government unable to do much of anything: unable to provide basic services (leading to mounting frustration with the government) and unable to properly run its security forces (who cannot contain the insurgents). Without some kind of political consensus on how to run the country, insurgent groups will keep finding fuel to light the fire. Or as one UN analyst put it: “Iraq will be stuck like this until Iraqi politics become mature enough.”

Polarized politics: What used to be a three-way power struggle between Shias, Sunnis and Kurds in Iraq has narrowed to Shias versus all Sunnis, Kurds included. “It’s not ethnic any more,” the UN analyst said. “It’s more sectarian.” Voices of reconciliation and moderation - which in 2008 might have called on civilians on both sides to be spared - have gone quiet. Maliki’s attempts to remove or arrest high-ranking Sunnis from government have not helped. “Acrimony in the political realm and the violence in the cities create a destabilizing feedback loop, whereby bloodshed sows mistrust in the halls of power and politicians are inclined to settle scores with their proxies in the streets,” says Ned Parker, a fellow at the Council on Foreign Relations and former Iraq correspondent for the Los Angeles Times. Those who threaten to expose the corruption of politicians are also persecuted.

Pre-election posturing/intimidation: High-profile targeted killings have increased, with much of the violence linked to politicians assuring their place in politics in the lead-up to provincial and national elections scheduled for 2013 and 2014 respectively. Many politicians have maintained links to the militias they used to control during the civil war and use them, as needed, to intimidate and hamper their opponents. Blowing up low-level explosives outside the home of a politician can serve as a warning sign to back off. (Cleric and politician Moqtada al-Sadr, leader one of the main Shiite militias, the Mahdi Army, found some in front of his home after he tried to push a no-confidence vote against the prime minister). Other attacks aim to make the government look incapable or even to eliminate a serving politician so as to replace him with someone else. Militias can also help politicians secure votes. Knights’ research has found the fastest-growing class of violence to be the "intimidation and murder" categories: close-quarters shootings, under-vehicle bombs, fatal stabbings, punitive demolition of property, and the kidnap of children.

Less intelligence: When US troops withdrew in December 2011, they took with them their intelligence collection mechanisms, leaving a gap in understanding of the security risks on the ground. “Troops and tanks cannot prevent the terrorist groups from operating. But intelligence can,” says Ali Al-Moussawi, media adviser to the prime minister. “Our intelligence is still not strong enough, still not harmonized, still not integrated.” Outsiders do not even trust the government to accurately report casualty figures. Observers point to evidence of significant insider government support for attacks, many of which would not be possible without collaboration from security officers in the police and intelligence service.

Anti-government sentiment: Many groups have diverted their focus from the US troops to the Iraqi Security Forces, seeing the US withdrawal as “trading one occupation for another”. Knights says Iraqi-on-Iraqi violence has increased by 15-25 percent since the pullout. Many of last week’s attacks were targeted at Iraqi government forces. Many analysts, including Toby Dodge of the International Institute for Strategic Studies, say Maliki’s attempts to centralize power are destabilizing Iraqi politics to the point they could push Iraq back into civil war. Iraqis regularly describe the government as “a bunch of thieves” and even Shias feel they have not benefited from billions of dollars of oil revenue that has poured into the country.

Marginalization: Sunnis do not feel the government in Baghdad represents them, viewing it instead as an anti-Sunni Iranian proxy. People in Sunni-dominated governorates like Diyala and Salaheddin have difficulty getting jobs, undergo waves of arrests, and face persecution by security forces. A second round of “de-Baathification” in state institutions late last year only made matters worse. “Sunnis feel at least as under siege as they ever did,” Knights says. They complain of central government intervention and intrusion into their local governments, and have increasingly been calling for regional autonomy. This feeling of marginalization - combined with high levels of youth unemployment - makes ripe territory for insurgent recruitment, or at least tolerance of militant activity on their soil. Insurgent groups have changed their messaging, away from anti-US rhetoric towards a government they describe as “Shiite-led pro-Iranian stooges… intent on dismembering Iraq and evicting Arabs from their homes,” Knights says. And many members of the Arab Awakening - a movement of Sunni tribal leaders who, in 2006, stopped fighting US troops, instead cooperating with them to root out al-Qaeda - have since rejoined the insurgency

But much of the resentment that insurgents feed on in Iraq is very localized. “It’s revenge,” Hiltermann says. “Revenge for having my brother in prison; revenge for not getting a job because the public sector is dominated by Shias; revenge for humiliation at a checkpoint.” These feelings of marginalization lead to very localized groups of al-Qaeda which can coordinate with each other, but have no joint overarching ideology. “It’s mostly reactive. It’s close to the ground,” Hiltermann says.

Territorial control: Analysts say al-Qaeda in Iraq, or AQI, the main Sunni insurgent group, appears to be resurging in the wake of the US withdrawal, and its leader, Abu Bakir Al Baghdadi, promised a new offensive a day before last week’s attacks. But to what end? It has made broad pronouncements of its intent to create an Islamic caliphate in Iraq - a pipe dream at best, according to most analysts. More realistic is an attempt to create Sunni fiefdoms that would have some degree of autonomy from Baghdad, but even that is a long way away. More than anything though, al-Qaeda-linked fighters in Iraq are driven by an attempt to regain territory and control lost during the US surge and the Arab Awakening. “They want to create havoc and hope to gain influence through that havoc, and at least restore Sunni power, at least `get the Iranians out’,” Hiltermann says.

Anbar Governorate, one of the areas in which al-Qaeda is most active, is rich in oil and natural gas reserves that have yet to be exploited. Control of Anbar would also give Sunni insurgents a base through which to support the armed opposition in Syria, which many analysts say has already begun happening. A Sunni government is likely to follow any fall of the current Syrian government, ruled by an off-shoot of the Shia sect. This has spurred a vision of a renewed “Sunni Crescent” stretching from Syria through Anbar, Diyala and Salaheddin governorates. Some parts of the desert have already become havens for militant activity. Likewise, cities like Mosul, where policing is weak, provide opportunities for insurgents to operate more freely.

Sectarianism: The Islamic State of Iraq, the political arm of al-Qaeda in Iraq, views Shiism as a theological schism within Islam - making Shias disbelievers and thus legitimate targets. Indeed, every year Shia pilgrims are targeted, as are “mixed communities” as a way of discouraging inter-sectarian harmony. And the more cynical say Sunni groups have increasingly turned to sectarian rhetoric after losing their anti-US rallying cry. Still, sectarianism is partially rooted in a genuine feeling that Shiite Iran has taken over Iraq: “There’s a clear sectarian pot-stirring attempt going on,” Knights says, “not because Al-Qaeda in Iraq wants to start a sectarian civil war in Iraq, but because they believe that sectarian civil war has already been happening for years and that regardless of what they do, the Shias will keep the Sunnis under the thumb and persecute them.” Still, sectarianism cannot be seen as a cause in isolation. Attacks on Shias in government are also linked to its perceived dictatorial nature. Attacks on Shia pilgrims can also be a way of discrediting the government by making it look incapable of protecting its own people. Sectarianism is an easy card for politicians to play in the interest of preserving their own power.

Local power brokering/score-settling: While many attacks are loosely blamed on al-Qaeda, the dynamic is more much layered, local and complex. Sunni-on-Sunni or Shia-on-Shia violence is not uncommon. In places like Mosul, which remains one of the more dangerous cities in Iraq, tribal politics are as much at play as any opposition to the central government.

In southern Iraq, various Shia militias and political factions - including Assaib Ahl al-Haq, the Mahdi Army, the Badr Corps, and Maliki’s Dawa Party - fight for control of various security agencies, key Iraqi Army formations, and regions, sometimes resulting in low-level skirmishes. Instead of targeting big visible national symbols, “most car bombings are now directed against Iraqis active in local politics, executed by terrorist cells based nearby. Insurgents are now focused squarely on the struggle for dominance of the neighbourhood police force, the sub-district council, the district courtroom, or vital pieces of terrain with local significance,” Knights says. “The lethality of bombings is of secondary importance; what these groups care about most is demonstrating their relevance, assuring their place in the post-US pecking order of militant movements, and attracting funding.”

A legacy of the civil war, score-settling is also at play. Sunnis of the Arab Awakening who collaborated with US troops against al-Qaeda are now vulnerable to revenge attacks. Once-persecuted Shias - and their parties - are still looking for retribution. It can be as simple as someone retaliating against the death of his neighbour.

Syria: The Iraqi government claims that violence in the country is already being accentuated by the crisis in Syria. Moussawi of the Prime Minister’s Office and Iraqi analyst Hadee Jalu Maree argue that open borders, a welcome, lawless environment for armed groups, and the cover of the rebel Free Syrian Army, allow al-Qaeda and other groups to move more freely, and plan and execute attacks on Iraq from Syria. Many analysts argue the trend is rather the other way around, with jihadist fighters leaving Iraq to fight the Syrian government - if anything, making Iraq safer.

But there is a general concern about what will happen to Iraq when all those fighters come flooding back, emboldened by what is likely to become a Sunni government in Syria that may be more sympathetic to using al-Qaeda in Iraq for its purposes. “There is potential for the insurgency to be reignited,” another UN analyst said.

Arab-Kurdish conflict: Low-level skirmishes continue in the disputed areas between Iraqi Kurdistan and the Arab areas controlled by the central government. JRTN (Army of the Men of the Naqshabandi Order), a militant Sunni group of former Baathists, is still active along the trigger line, where the US military surge never quite reached. As tension rises between Baghdad and Kurdistan’s capital Erbil over oil revenues and power-sharing, groups like JRTN take advantage of the vacuum. But theses skirmishes are unlikely to flare up into all-out conflict. Both sides have too much to lose.

Crime: With insecurity driving away investors, and nearly a quarter of the population living in poverty, according to the UN Inter-Agency Information and Analysis Unit, financially-motivated kidnappings are rising. In places like Mosul and the Syrian-Iraqi border, violence can be linked to organized crime, smuggling, and protection rackets. Personal disputes or disputes between contractors are also contributors. (IRIN)